A torsion spring is typically provided in a servo valve, for example an electrohydraulic servo valve incorporating a flapper nozzle assembly. The torsion spring may be connected to the armature of the servo valve to bias the armature and the component connected thereto (e.g., the flapper) towards a rest position. The torsion spring may, therefore, be seen as a negative feedback mechanism to the movement of the magnetic armature.
Due to the tolerances and small movements in a servo valve, the stiffness of a torsion spring has to be determined and manufactured precisely. Furthermore, a torsion spring will typically be subject to a high number of use cycles (e.g., 10 per minute), and resistance to fatigue is also an important factor when designing and/or manufacturing this component.
It is desired to provide an improved torsion spring, and improved methods for manufacturing torsion springs.